1. Field of the Invention
The present invention relates to high frequency signal propagation using printed circuit boards (PCBs). In particular the present invention relates to a PCB with a removal portion of a layer alongside a signal transmission strip such as a microstrip on the PCB in order to reduce signal attenuation along the propagation path of a high frequency signal.
2. Brief Description of the Related Art
As the speed of signals propagating on PCBs made of certain dielectric materials increases, the ability for conventional signal traces to carry such signals is limited. Current manufacturing techniques involve microstrips with dielectric material surrounding the microstrip. The use of dielectric material surrounding the microstrip causes undesirable attenuation of high frequency signals propagating via the microstrip referred to as dielectric loss. It is appreciated by those of ordinary skill in the art that the effective frequency of a central processing unit (CPU) on a PCB is limited by the dielectric loss of the microstrip.
Many systems are available for affecting signal propagation. In U.S. Pat. No. 6,441,313 B1 issued on Aug. 27, 2002 to Novak, a layered circuit board is described where the thickness of a dielectric layer can be reduced to reduce high frequency losses between power and ground planes and signal traces. In U.S. Pat. No. 6,137,383 issued on Oct. 24, 2000 to De Lillo, for example, evanescent mode waveguide filters can be constructed using via holes conductively connected to capacitors to form narrow band filters. De Lillo suffers from the need to engage in complicated plating and processing of via holes to achieve filtering and is effective only to provide a narrow band filter within a limited physical space dedicated to filter construction and thus fails to describe reducing propagation losses due to the dielectric characteristics of, for example, an insulative layer or dielectric layer.
Thus it would be desirable in the art for a simple solution to reducing propagation losses for signals traveling on a microstrip on a PCB. An exemplary solution would be simple to construct and reduce losses over a wide range of high frequencies capable of being generated in a modem high speed processor.